Servers are known in a number of different contexts. For example, in 3GPP (Third Generation Partnership Projects) or IP (Internet Protocol) architectures, users may subscribe to subscription services. An example of a subscription service is presence. The subscription service is initiated using subscription messages. In one known system, the subscription messages utilize SIP (session initiation protocol) messages. On detection of a subscribed event, a subscription server notifies the subscriber of the event using notification messages. In known systems, the subscription and notification messages are facilitated by a proxy server configured as a connection processing server (CPS). The subscription establishes an SIP dialogue through the CPS, and the CPS maintains that dialogue and it is used for all notifications. In this way, the CPS effectively records the route of the subscription.
The number of requests which can be served by a server may be limited. Servers may be arranged to implement mechanisms to protect the server from overload, for example load balancing in which the load rate is measured constantly and taken into account when making routing decisions, so that no single server gets overwhelmed. Overload conditions may occur if the request rate is too high. These overload mechanisms deal with overloading the server. However, none of the available solutions consider limiting the number of requests which are handled.